This application is a continuation-in-part of my earlier parent application Ser. No. 856,740, filed Apr. 28, 1986, now abandoned.
A prior-art thermal ink jet printhead 2 is shown in FIG. 1. The advancement of thermal ink jet (TIJ) technology stumbles upon an assembly problem: detachment of the nozzle plate 1. Presently, each nozzle plate 1 is individually attached to the resistor structure 3 as shown in FIG. 2A. This costly procedure is problem-prone. For example, this procedure often misaligns the nozzle plate 1. FIG. 2A, a simplified representation of the prior art, omits many of the details. The differences in thermal expansion coefficients among different components of the TIJ printhead 2 tend to debond the nozzle plate 1 during the curing process of the glue. This adhesion problem limits the number of nozzles in the TIJ printhead 2.
The ink refilling rate of prior-art TIJ printhead 2 presents another problem. It limits the printing speed. In prior-art TIJ printheads 2 shown in FIG. 2B, ink reaches the nozzle 6 after traveling through high friction channels 7 which restrict the ink flow.
The invention described in U.S. Pat. No. 4,438,191, Monolithic Ink Jet Print Head, incorporated herein by reference, proposes a monolithic ink jet printhead that would solve some of the problems listed above. However, the fabrication of this device presents additional problems: formation of ink holes, removal of dry film residue from the firing chambers and other locations, proper alignment of the nozzle, and various manufacturing problems. Also, the nozzles of the monolithic printhead do not diverge.